Sheet separator air blast nozzle



April 29, 1952 G. F. WATSON 2,594,373

SHEET SEPARATOR AIR BLAST NOZZLE Filed March 5, 1950 \\\\\\\\\\\v 5 9 V ewa Patented Apr. 29, 1952 SHEET SEPARATOR AIR BLAST NOZZLE George F. Watson, Racine, Wis., assignor to The Christensen Machine Company, Racine, Wis., a

corporation of Wisconsin I Application March 3, 1950, Serial No. 147,375

Claims.

This invention relates to sheet feeders for feeding sheets off a pile or similar supply thereof to a printing press or other machine, and refers more particularly to means for separating the rear edge portions of the topmost sheets preliminary to complete separation and advance of the topmost sheet toward the machine being fed.

Present day stream feeding of printing presses requires the sheets to be fed from the back edge This is ordinarily done by directing a blast of forwarding air under the topmost sheet while the same is held and controlled by so-called forwarding suckers which engage the sheet at its rear edge portion and move forwardly a distance sufficient to permit the sheet to be advanced into the bite of the feed-off rolls located at the front edge of the pile.

Obviously to enable the topmost sheet to be so grasped by the forwarding suckers and advanced by the blast of forwarding air preliminary sep arationof the topmost sheets is necessary and, of course, all of the sheets below the topmost sheet must be held down during the time the top sheet is forwarded.

Preliminary separation of sheets has long been a problem, especially where the sheets to be fed. are large. In the past it has ordinarily been done by combing wheels which are moved into engagement with the rear opposite corners of the top of the pile and rotated toward each other to act against stops and thereby comb humps into the topmost sheets; but combing wheels have inherent disadvantages. They require considerable mechanism for their operation and in addition often mar or injure the surface of the sheets. I The art has long been cognizant of these disadvantages of the conventional combing wheel separators and periodically attempts have been made to supplant the combing wheel with an air blast type of separator. A recent attempt in this direction is disclosed in the patent to L. C. Williams, No. 2,434,530, issued January 13, 1948, but since the separator of this patent depends upon blowing air simultaneously against the side and rear edges of the pile, the location of the preliminary separation obtained thereby is constrained to the exact rear corners of the pile. This is a serious limitation since the most advantageous location for the forwarding suckerswhich determines where preliminary separation should be concentratedis often a substantial distance in from the sides of the sheet and not necessarily the same distance for all widths of sheets.

Thepurpose of the present invention, therefore, is to provide air blast means for effecting preliminary separation of the topmost sheets of a pile in a manner which does not constrain the point at which maximum separation occurs beyond requiring the same to be located adjacent to the rear edge of the pile.

Stated in another manner, it is an object of this invention to provide means for effecting preliminary separation of the topmost sheets of a pile by an improved air blast means capable of adjustment along the rear edge of the pile so as to enable the same to be most effectively located, namely, directly behind the forwarding suckers.

According to this invention two vertically elongated laterally spaced jets of air issuing from the hollow interior of the nozzle head are caused to flow a distance forwardly therefrom in unconfined streams before forcefully impinging defleeting surfaces at the mouth of the nozzle, with such angular disposition of the deflecting surfaces and the streams of air striking them that the air is deflected toward a zone centrally of the nozzle mouth as it issues-therefrom to create a highly turbulent forwardly moving body or blast of air to act upon and have the best possible separating effect on the topmost sheets of a pile thereof.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawing illustrates one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a more or less diagrammatic perspective view illustrating the rear edge portion of a pile of sheets with the preliminary separating mechanism of this invention in operative relation thereto;

Figure 2 is a top plan View of one rear corner portion of the pile and the preliminary separating device of this invention positioned in operative relation thereto, said view having par-ts thereof broken away, and in section; and

Figure 3 is a view in side elevation of the structure shown in Figure 2.

Referring now particularly to the accompanying drawing, the numeral 5 designates a pile or equivalent supply of sheets, the topmost of which are to be successively and singly fed off thepile to a printing press or other machine (not shown).

To enable stream feeding of the sheets in which the successive sheets underlap the advancing stream of previously fed sheets, the entire separating and forwarding operation is performed line It).

(not shown) but as is well known, located at the front of the pile or supply of sheets. As is customary, the suckers 'l and their operating mechanism (not shown) are adjustable crosswise of the machine to accommodate different width sheets and permit the suckers to be most edventaseonsly oca e To enable the forwardin Suckers to grasp the topmost sheet it is, of course, essential that it be separated from the rest of the pile and to eflect such preliminary separation the present invention provides novel air blast nozzles ,8, one

behind each forwarding sucker l.

lhese nozzles are identical and each comprises ahollow arm 5) .to which air under pressure is fed by a pressure Like the suckers 1, the nozzles 8 are adjustable along the rear edge of the pile. Any suitable means maybe employed to mount the nozzles, as for instance, a fixed cross rod Ii (omitted in Figure 1 for clarity) upon which the nozzles are slidably mounted.

The hollow arm opens to a substantially rec- 'tah ular hollow head l2 which serves as a manifold. The front wall it of the head has two laterally spaced vertical slits 14 therein providing air discharge orifices. The air issues from these orifices in unconfined narrow ribbon-like jets or streams and flows :3. distance forwardly ircm the head before impinging forwardly converging deflector walls I5. The walls 35 deflect air impinging their inner surfaces forwardly and toward a zone centrally of the mouth or outlet of the nozzle which is defined jointly by the deflector walls #5 together with top and bottom walls l6 and H respectively. As shown the deflector walls extend slightly forwardly of the front ed es of the top and bottom walls to lie closely adjacent to the pile of sheets; and they join with the front wall 13 at areas spaced a distance laterally from the mouths of the dircharge orifices U! to assure that the air issuing therefrom will flow a distance forwardly into the mouth of the nozzle in unconfined streams before striking the deflecting surfaces.

To enable assembly of the front manifold wall [3 with the nozzle, which is preferably a casting, the wall I3 is constructed of two plates each onehalf the full length of the wall, the contiguous edges of these plates being welded together as at 18 after assembly.

As indicated, each nozzle is mounted for lateral movement along the back edge of the pile and is so positioned that its mouth is closely adjacent to the rear edge of the. pile at the upper portion thereof and directly to the rear of one ofthe forwarding suckers 1. So positioned the zone of intersection of the converging planes of the deflector walls i 5 lies well within the pile of eheets and near the point at which the adjacfint forwardingsuch-er is to grasp the topmo tshe T confin e irms or p l m nar separationjo f the sheets to the side portions of the pile a conventional hold-down or presser foot I9 engages the top of the pile laterally inwardly of Ea h BUZZE- The timing of the mechanism in the operation of the machine as is well known to those skilled in the art is such that the presser feet I9 first engage the top of the pile and then directly thereafter the preliminary separation begins which, in this case, entails merely the opening of the valve (not shown) controlling the admission of air under pressure to the nozzles 8. Next, vacuum comes on at the forwarding suckers 1 which at this instant are at their rearmost and lowermost positions. The top sheet is then gripped by the forwarding suckers and the suckers begin their forwarding motion preceded, if desired, by a lateral or outward movement to tension the sheet across its rear edge.

As soon as the sheet has been gripped by the forwarding suckers the presser feet l9 are moved off the top of the pile and the forwarding air blasts issue from the nozzles 6, and then the separating air is cut off from the nozzles '8. As soon as the top sheet is advanced a distance sufficient to accommodate the presser feet these elements are restored to their operative positions clamping down upon the top of the pile, whereupon the cycle is repeated.

It has been found that the preliminary separation obtained with the nozzles of this invention surpasses the preliminary separation produced by separating mechanisms heretofore employed in sheet feeders, and while the reasons why the nozzles so greatly improve the separating action is not entirely understood, it is believed that an exceptionally great turbulence is created in the forwardly moving blast of air issuing :from the mouths of the nozzles, as indicated by the arrows in Figiu-e 2, and that this turbulence is needed within the adjacent portion of the pile to retard the outward displacement of the air and thus effect a greater separation between sheets.

It has also been established that the location of the nozzles should be directly behind the forwarding suckers and since the location of these suckers with respect to the side edges of the sheets depends upon the size of the sheets and is, therefore, not constant, it follows that the adjustability of the separator nozzles 8 along the rear edge of the pile is a very important advantage of this invention.

What I claim as my invention is:

1. A fiufling nozzle for sheet feeders for effecting preliminary separation of the topmost sheets of a supply thereof, comprising: means defining a hollow nozzle head having an air inlet; means including two forwardly extending side walls on the front of the head defining an air outlet; said head having two discharge orifices opening to the front thereof and spaced a distance laterally from one another and from said side walls, through which air supplied under pressure to the hollow interior of the head issues to flow forwardly in unconfined streams. in the nozzle outlet, said side walls and the orifices being so angularly disposed relatively to one another that the air issuing from each orifice impinges the side wall adjacent thereto at an angle and at an area thereof located a distance ahead of its junction with the front of the head so that the air impinging the side walls is deflected inwardly toward. a zone centrally between the side walls as it passes forwardly out of the nozzle outlet.

2. The flufling nozzle set forth in. claim 1 wherein said side walls are upright and converge forwardly toward one another; and wherein said discharge orifices are substantially upright slits 5 in the front of the head parallel to the side walls but spaced a distance laterally inwardly from their junctions with the front of the head.

3. A flufiing nozzle for sheet feeders for effecting preliminary separation of the topmost sheets of a supply thereof comprising: means defining a nozzle head having two discharge orifices opening to the front thereof and spaced laterally from one another; air inlet means on the head communicating with said orifices and by which air under pressure may be supplied to the head to flow forwardly from said orifices in unconfined streams; and means on the head for combining air issuing from said orifices into a forwardly moving turbulent blast as it leaves the nozzle, comprising two deflector walls joined to the front of the head at two opposite sides thereof and at areas spaced laterally outwardly from said orifices, said deflector walls extending forwardly from the head and having deflecting surfaces spaced a distance ahead of the mouths of the discharge orifices and arranged in the path of' deflector walls but spaced a distance laterally in wardly from their junctions With the front of the head.

ing preliminary separation of the topmost sheets of a supply thereof comprising: a hollow nozzle head having a front wall; air inlet means on the back of the head providing for the supply of air under pressure to the interior of the head; means on the head at its front providing a forwardly opening outlet for the nozzle; said front wall of the head having two laterally spaced upright slitlike discharge orifices therein communicating the air inlet and outlet means and from which air under pressure in the hollow interior of the head issues to flow forwardly in unconfined streams into the outlet means; and two forwardly converging defiector walls on said outlet means having surfaces thereon spaced a distance forwardly of said orifices and lying angularly across the path of air issuing therefrom to be impinged by said air and cause the same to be deflected toward the central zone of said outlet means for discharge therefrom.

GEORGE F. WATSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,214,088 Seybold Sept. 10, 1940 2,302,021 Freeman Nov. 17, 1942 2,402,441 Perry June 18, 1946 2,439,530 Williams Jan. 13, 1948 FOREIGN PATENTS Number Country Date 660,836 France July 17, 1929 

